<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <style>

        div{
            background-color: yellow;

        }

    </style>
    <link rel="stylesheet" href="/demo03/static/css/a.css">

</head>
<body>

<div>
    hello div
</div>

</body>
</html>